My own preferred statement of The Theory of Global Warming is this:
An increase in the atmospheric concentration of CO2 and other long lived greenhouse gases requires the surface temperature to ultimately increase so as to maintain a balance with the absorbed solar radiation. The increase is amplified by water vapor (also a greenhouse gas), which increases with temperature in such a way as to keep relative humidity approximately constant. Melting of ice will further amplify the warming, particularly in high latitudes. The resulting widespread warming corresponding to a doubling of CO2 will be large enough and rapid enough to be well outside the range of past experience of the human species, by an amount comparable to the difference between a glacial and interglacial climate. Changes in atmospheric cloud properties may somewhat reduce or increase the sensitivity, but do not substantially alter the conclusion.
The last part of the statement of the theory is, of course, the hard part, and the most uncertain.
I have deliberately left the matter of the severity of the impacts of such a climate change out of the hypothesis. Theories regarding the impact are nascent and in many regards still rather ill-formed, in comparison to the theory dealing with the physical dimensions of climate change. Also, insofar as there are uncertainties about the severity of the impacts of climate change, it is a matter for the political apparatus to decide how to deal with the uncertainties, and the extent to which one should pay attention to the worst case vs. the most likely case. The question of how to factor in the uneven distribution of harms (and possibly benefits) across the peoples of the Earth, and between human societies and natural ecosystems, is also at heart a matter of ethics and values. These are questions that can be informed by science, but they are not themselves scientific questions.
http://www.realclimate.org/index.php/archives/2006/02/happy-birthday-charles-darwin/
It's not that hard to say what you mean when you say "AGW" or "global warming". It's also not hard to explain what the predictions are, and how we measure objective reality, so we can determine if the theory is accurate. Refusing to explain these things, or worse, saying there are no predictions, or there is "no theory" is classic pseudoscience.
Some pseudoscientific claims can't be tested because they are consistent with every imaginable state of affairs in the empirical world, e.g., L. Ron Hubbard's engrams. Scientific theories not only explain empirical phenomena, they also predict empirical phenomena. One way we know a scientific theory is no good is that its predictions keep failing. Predictions can't fail unless a theory is falsifiable. Some pseudoscientific claims can't be falsified because they are consistent with every imaginable empirical state of affairs.
http://www.skepdic.com/pseudosc.html
Obviously we see many predictions made by global warmist, as well as claims that the predictions have already been confirmed! So when somebody claims there is no theory, or it's made up, or only used by "deniers", they obviously don't know what they are talking about. "Scientific theories not only explain empirical phenomena, they also predict empirical phenomena." That future warming is predicted is exactly the sort of thing that a scientific theory is about.
The jackbooted warmists might want to tell you (more like ram it down your throat hole) that "AGW is a fact, not a theory", but that is more pseudoscience.
Laws differ from scientific theories in that they do not posit a mechanism or explanation of phenomena: they are merely distillations of the results of repeated observation
https://en.wikipedia.org/wiki/Scientific_law
scientific theories are inductive in nature and aim for predictive and explanatory force.
https://en.wikipedia.org/wiki/Scientific_theory
Some here seem to think AGW is a scientific law, not a theory. This is a very stupid thing to believe. Especially when combined with the stupid concept of
There is no such thing as the "Theory of Global Warming" as you have actually found out!
It appears because people like you trot it out. It doesn't appear in the scientific literature.
There is no such thing as a Theory of Global Warming, the expectation that there would be indicates a profound misunderstanding of the nature of climate science.
What's a scientific person to think of such absurd claims?
Not only do scientific articles discuss the term, they define it, and talk about the predictions from it.
Global Warming –
Theory which states that an increase in carbon dioxide and other gases in the
atmosphere results in an additive effect on average global temperatures.
http://sites.wff.nasa.gov/code250/docs/PFRR_EIS/FINAL - Volume I Individual Files/Ch 8 Glossary.pdf
Is global warming the figment of some scientists' imaginations? How can we reconcile
the global warming theory with the reality of what we find when we step outdoors?
http://data.giss.nasa.gov/gistemp/2004january/
How Dry is the Tropical Free Troposphere?
Implications for
Global Warming Theory
http://science.nasa.gov/science-news/science-at-nasa/1997/essd14jul97_1/
Global Warming Theory Affirmed
http://earthobservatory.nasa.gov/Newsroom/view.php?id=21241
Sometimes people ask "what would it take to falsify
the man-made global warming theory?". Well, basically it would require that our fundamental understanding of physics be wrong, because that's what the theory is based on.
http://www.skepticalscience.com/big-picture.html
If changes in CO2 began after changes in temperature, didn’t that contradict
the greenhouse theory of global warming?
http://www.aip.org/history/climate/co2.htm
One of the predictions that arise from
the theory of Global Warming is that as the climate system warms, as more energy accumulates in various parts of the system, weather in various ways will become more intense and also more erratic.
http://www.skepticalscience.com/print.php?n=1296
So don't lie and say stupid things, it will come back to haunt you.